Am I too fat? Do I need to loose weight?

C

Crisp image

Member
I have built my DJI F450 and it flys really well. That was until I added some landing gear, gimbal and Gopro.
Now when I take off the whole quad vibrates violently.
I am using standard DJI motors and 8 inch props with a 4s 5000mah battery. AUW is 2kg
I had a play with the gains but nothing changed.
Am I too heavy?
Do I need to go on a diet?
How do others have all this gear in their quads and still fly?
Don't be shy. Tell me what you think.
Regards
Crispy
 

Roger Ramjet

Roger Ramjet

Member
I found that 400 g per motor seems to be the confortable limit for DJI stock motors (2212, 920 KV). Of course, it is possible to fly at higher weight but it can become touchy with gusty wind and downdrafts. This puts a confortable limit in the 1600 - 1700 grams range.

The vibration problem is more likely associated with an unbalanced prop. Recheck prop balancing and you may use a free intelligent phone application for vibrations analysis on X, Y, Z axis by strapping your phone on each arm and conducting some ground testing. A particular value may be hard to assertain but the importance is to validate that the vibration level is similar on each arm rather than determining a precise value. Regardless of your weight, the vibration problem must be solved first.

The use of a larger prop is also beneficial when operating at higher weight, but you have to be careful not to exceed you motor max current
load. I have gone from DJI 920 KV to SunnySky 800 KV (cheap and excellent motors) and I noticed an important difference. With this in mind, you will be in better shape I believe.

IMHO, 2 Kg on F-450 is pushing it beyond confort... For the difference in price, you may want to consider a F-550 if you must fly over 2 Kg. The F-550 is very confortable at 2400 - 2600 g with stock motors. I personnally fly a F-550 at around 3 Kg with the SunnySky 800 Kg on 3 S and 12 X 3.8 props.

Hope its helps...
 


A

Arrow-Eye

Member
Hi, Crispy:

If you change the weight, you have to adjust the gains for your flight controller, do you use Naza-M?
And possibly, the C.G has been changed, probably you need double check your GPS and IMU position, but normally that doesn't matter too much.
And agree with Roger and PeteDee, the propeller also could be the cause.
 

C

Crisp image

Member
Thought as much with the weight. I have some 10 inch props so will try with those. Which sunny sky motors do you use? I take it its not the angel ones that are half the size of the others.
Other options is a hex. Either way a couple of hundred dollars will need to be spent. I owe I owe its off to work I go!
Well that is where I am at the moment.
Regards
Crispy

Sent from my GT-I9210T using Tapatalk
 

LeeT

LeeT

Wannabe AP Dude
Crisp image said:
Thought as much with the weight. I have some 10 inch props so will try with those. Which sunny sky motors do you use? I take it its not the angel ones that are half the size of the others.
Other options is a hex. Either way a couple of hundred dollars will need to be spent. I owe I owe its off to work I go!
Well that is where I am at the moment.
Regards
Crispy

Sent from my GT-I9210T using Tapatalk
Click to expand...
Not to take anything away from SunnySky motors, I fly them in my other quad., I was using T-Motors 2216-11 on my F450, w/ 10x4.5 props with AUW appox 2200 (gimbal,FPV,etc) with no issues. Check ecalc it will give you a good idea of what props, batteries etc will let you do "what ifs" with different props, motors, configurations etc to come up with what works best for you. My former F450 is now a F650 2650 AUW with approx 10 minutes flight times.
 

C

Crisp image

Member
Well I am at home now and have put the 10 inch props on.
It did fly but I think the motors over heated a bit and it would not climb any higher so I had to land.
So I guess I am looking at 2 options
1. Replace the motors and props with something with more thrust
2. build a hex using the parts from my quad.
I know there are a couple of suggestions so far but what else is there available.
Are any of the hobby king products ok?
Looking at something like these
http://www.hobbyking.com/hobbyking/...s_28_30S_900kv_270w_short_shaft_version_.html
Regards
Crispy
 

S

stitch1615

Member
Crisp image said:
I have built my DJI F450 and it flys really well. That was until I added some landing gear, gimbal and Gopro.
Now when I take off the whole quad vibrates violently.
I am using standard DJI motors and 8 inch props with a 4s 5000mah battery. AUW is 2kg
I had a play with the gains but nothing changed.
Am I too heavy?
Do I need to go on a diet?
How do others have all this gear in their quads and still fly?
Don't be shy. Tell me what you think.
Regards
Crispy
Click to expand...

I have a near identical setup but fly 5000 3S battery with 10" gemfan props and it is stable as a rock with the default settings on Naza V1.
I'd check the prop balance and copter balance itself.
 

COMike93yj

COMike93yj

Still Building!
Crisp,

I am not familiar with Short shaft motors but I believe you need some sort of accessory pack with it. I am not certain if it comes with one so you might want to ask on the NTM motor you are looking at.

Mike :)
 

jfro

jfro

Aerial Fun
COMike93yj said:
Crisp,

I am not familiar with Short shaft motors but I believe you need some sort of accessory pack with it. I am not certain if it comes with one so you might want to ask on the NTM motor you are looking at.

Mike :)
Click to expand...

I had my f450 at a little under 2150 grams AUW. Use 30amp simonk esc's with Tiger 2216 900kva motors and 10" APC 10x4.5 props. Flies like butter and motors never come down warm.
Extended it to 550 with aluminum arms. That is my current 2150 g of weight. Still flies great. 1- 5000mAh 4s battery and I can push 20 minutes without the tarot gimbal/ gopro 3.
With gopro and gimbal, I safely fly 12-13 minutes on most of my batteries.

eCalc tells me I'm over amped at wide open, but these are the motors the discover FPV peeps use. Since it flies so nicely and the motors are always cool, I don't worry about it.

I would highly recommend the tiger 2216-11/ 900kv motors.

My setup is an absolute joy to fly. I'm mostly video, so i don't fly fast.....
 

C

Crisp image

Member
So t motor with 4s battery and 1045 props are good. What is the Prop recommendation for sunny sky with the 4s battery to get the most thrust out of them?
Regards
Crispy.


Sent from my GT-I9210T using Tapatalk
 

C

Crisp image

Member
Ok so thanks to the comments here I have purchased some T-Motors 900kv for a great price of $38 aud and they are here in Australia (PeteDee you may be interested in this) but I will have to wait for a week till they reopen for them to be sent. I have also purchased some 1045 props to go with them. I will update this thread when I get the gear and fit it up.
Regards
Crispy
 

jfro

jfro

Aerial Fun
Crisp image said:
Ok so thanks to the comments here I have purchased some T-Motors 900kv for a great price of $38 aud and they are here in Australia (PeteDee you may be interested in this) but I will have to wait for a week till they reopen for them to be sent. I have also purchased some 1045 props to go with them. I will update this thread when I get the gear and fit it up.
Regards
Crispy
Click to expand...

I think you will be very happy with your decision. And you did get a good price on the motors.
 

C

Crisp image

Member
The T motors turned up today while I was at work. I have fitted them up and had a 30sec flight with 1045 props. Well it all seems good.
I will fly a couple of test packs tomorrow if the wind stays away for some time.
I will let you know the results
 

C

Crisp image

Member
well I took it for flight today and all was well until I had an oops and landed in a tree about 30 to 35 metres up. I attempted to climb it but ran out of options after 25m so I called the city council and one of their tree blokes came and retrieved it for me. 3 broken props and a dented pride was all the damage. I'll post the video in the next day or so. For now it will be clear fields for me!
Regards
Crispy

Sent from my GT-I9210T using Tapatalk
 


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